"Man, I'm real excited,'' said Allen, who was picked up by St. Louis after being cut by Carolina on Saturday. "Second chances are hard to come by in this league. Carolina didn't work out, it was tough not getting many reps or having a chance to show what I could do, but it's a business.''

Allen said St. Louis and Tampa Bay courted him after he went undrafted in the May NFL draft, but at the time he felt the fit was better with the Panthers, so he signed with them as a free agent.

"But then I only played in three preseason games and had limited reps,'' Allen said. "I learned you have to take advantage of every opportunity you are given, every single rep, and you take every note.''

Allen said the Rams called within 10 minutes of the time his name appeared on the Panthers' release list on Sunday.

"Now it's about how fast I can transition,'' Allen said. "I got to get the playbook down and compete, it's all on me.''